Treharris (Merthyr Tydfil) weather

Headline:

Turning clearer and drier from the west overnight.

This Evening and Tonight:

Staying very wet for many this evening with further flooding and travel disruption possible. Gradually becoming drier from the west overnight with skies clearing. A colder night than recent, with pockets of ground frost and fog possible later. Minimum temperature 2 °C.

Tuesday:

Any mist and fog clearing, then a dry and increasingly bright day with some sunshine developing for many of us. Not as mild, albeit with light winds for all. Maximum temperature 9 °C.

Outlook for Wednesday to Friday:

Turning windier on Wednesday with coastal gales and further rain at times, this likely heavy and persistent by Thursday. Bright and breezy on Friday with sunshine and isolated showers. Mild.

The unsettled theme is likely to continue through the first part of this period, with further rain or showers affecting many parts at times, and often accompanied by rather windy conditions. In the run up to Christmas, there is a signal for less unsettled conditions to begin to take hold, with a greater chance of high pressure developing in the vicinity of the UK compared to the previous few weeks. Whilst the chance of impactful rain or strong winds should reduce, there may be an increasing incidence of overnight frost and fog, the latter perhaps taking its time to clear, given the time of year. A gradual reduction in temperatures seems likely, falling closer to average overall. Some cold days are possible, if or where any fog persists.

High pressure will probably be close by to the UK at the start of this period, which would maintain a fair amount of dry, settled weather. With this comes the potential for fog and frost, and lower temperatures overall, though nothing unusually cold is currently signalled. Towards mid-January, perhaps a greater chance of more changeable conditions re-asserting themselves, though this is rather uncertain at present.